This undated publicity film image released by Paramount Pictures shows, Zoe Saldana, left, as Uhura and Zachary Quinto as Spock in a scene in the movie, “Star Trek Into Darkness,” from Paramount Pictures and Skydance Productions. (AP Photo/Paramount Pictures, Zade Rosenthal)

LOS ANGELES — “Star Trek Into Darkness,” the second installment in director J.J. Abrams’s reboot of the science-fiction series, is forecast to take in $112 million in its debut, boosted by an early start in theaters this weekend.

The film, from Viacom’s Paramount Pictures, opened Thursday in U.S. and Canadian cinemas, a day earlier than originally planned, to maximize its chances in a crowded schedule. “Star Trek” targets the same young males as “Fast & Furious 6” and “The Hangover III,” which open next week.

The extra day means Trekkies will spend more on tickets this weekend, although some viewers will simply shift to Thursday. “Star Trek” is forecast to reach $300 million in domestic ticket sales, second this year to Walt Disney Co.’s “Iron Man 3,” according to researcher BoxOffice.com.

“Squeezing the most profit out of your pictures is essential over the summer season,” said Jeff Bock, senior analyst for Exhibitor Relations Co. “There’s too much competition and you really have to make your mark in the first couple of weeks.”

Paramount, owned by Sumner Redstone’s Viacom Inc., moved the release about a week ago. The change may help the film capture college students home for summer, according to a studio spokeswoman. The film was made for about $190 million, Box Office Mojo estimates.

Warner Bros. is also opening “The Hangover III” on a Thursday next week, on May 23. The studio is planning to exploit the long Memorial Day Weekend, as it did with the second “Hangover” in 2011, said Dan Fellman, head of domestic distribution at the Time Warner Inc. unit.

The Thursday openings make sense given the level of competition, Bock said.

In April, BoxOffice.com was projecting a $128 million opening for “Star Trek.” Had the studio stuck with a three-day schedule, it still would have surpassed $100 million, said Boxoffice.com’s Phil Contrino.

Strong sales for “Star Trek” would build on the summer momentum established by “Iron Man 3.” As the weekend approached, the film was poised to surpass $300 million in domestic sales and $1 billion worldwide for Disney’s Marvel.

This year, Hollywood has lacked huge blockbusters. Last year’s “Marvel’s The Avengers” and “The Hunger Games” had each generated almost $400 million domestically by now. Industry ticket sales totaled $3.38 billion as of May 15, down 13 percent, according to Box Office Mojo.

“The box office has been sluggish,” Bock said. “Now we’re finally starting to see a return to form.”

“Iron Man” is forecast to add $31.5 million to its total this weekend. Director Baz Luhrmann’s “The Great Gatsby,” starring Leonardo DiCaprio and buoyed by strong interest from female moviegoers, is set to gain another $22 million for Warner Bros., adding to its $63 million total, according to BoxOffice.com.

“Star Trek” accounted for 71 percent of sales on online ticket vendor Fandango.com, the company said on May 14. For the traditional three-day opening period of Friday through Sunday, the ticket sales are projected to reach $87 million, according to Boxoffice.com. That would also be second this year to “Iron Man 3.”

The 2009 “Star Trek,” featuring a young USS Enterprise crew just out of Starfleet Academy, took in $257.7 million in the U.S. and Canada.

Abrams’s fresh approach to the material, as well as the successful introduction of actors Chris Pine as Captain James Kirk and Zachary Quinto as Spock, drew in a broader group of fans than the series’ loyal Trekkies. The movie drove strong word-of-mouth sales, according to BoxOffice.com.

In the new film, Kirk and Spock chase down a nefarious new villain, played by British actor Benedict Cumberbatch. The movie also offers a 3-D version that the first one didn’t.

“Star Trek Into Darkness” was called “smart, emotionally resonant and staking a 21st-century claim on Gene Roddenberry’s 1960s humanism,” according to Bloomberg critic Greg Evans. It met with 87 percent approval among reviewers tracked by the website Rottentomatoes.com.

“Abrams goes at warp speed into a universe that, after 11 movies, should be a tired, shriveled red dwarf by now,” Evans wrote. “Instead, ‘Darkness’ is a blast.”

“Star Trek” is one of Paramount’s biggest franchises, along with “Transformers,” and has financial backing from David Ellison’s Skydance Productions.

The latest film will attract new viewers as well as older fans of the 1960s TV show and movies made in the following decades, said Contrino, chief analyst for Boxoffice.com.

“Obviously, it’s building a younger base of fans who’ve probably never watched an episode of the TV show, and they’re also waking up the old fans,” Contrino said.